An amplitude-shift-keyed (ASK) optical transmitter is described for generating an ASK modulated infrared signal from a light-emitting-diode (LED). The transmitter includes a DC powered microcircuit for generating an ASK modulation signal. A pair of mosfet devices are connected in series with one or more LED's between the mosfets. An oscillator signal used to operate the microcircuit is also employed as a carrier signal to activate one mosfet while the ASK modulating signal is coupled to operate the other mosfet. Input capacitances of the mosfets are used to tune the oscillator signal and smooth the leading and trailing edges of the ASK modulation signal. Several embodiments are described.

A high voltage measuring system with very high input impedance. The system measures a high voltage source under test by developing a control signal which is proportional to the differential voltage between the high voltage source being tested and an adjustable high voltage reference. This control signal is fed back into a controller which adjusts the reference source so as to match the reference source with the source under test. When the controller detects that matching has occurred, it measures the reference source. By measuring the reference source, as opposed to measuring the source under test directly, the system avoids loading down the source under test.

A channel electron multiplier phototube having a channel electron multiplier, a transparent faceplate, and an anode assembly. The channel electron multiplier includes an insulating body having a curved passageway extending therethrough. A photoemissive element, and a secondary emissive dynode material is on the walls of the passageway. The passageway, together with a photoemission film of the photocathode assembly and the anode of the anode assembly define an evacuated closed region. Preferably, the electron multiplier is a monolithic ceramic body.

Disclosed is a system comprising a plurality of networks, encapsulated in substantially electrically non-conductive materials and positioned interior to the outer surface of an encasement region. According to the invention, at least one outer surface of at least one of the encapsulated networks is complementary to, adjacent to, and in physical contact with at least one outer surface of at least one other of the encapsulated networks. Also disclosed is a method for constructing the system. In a preferred embodiment, the system is a toroidally shaped power supply whose modular structure facilitates ease of testing and assembly, affords considerable space savings, substantially reduces manufacturing waste costs, and eliminates a proven source of circuit failure.